1. Field of the Invention
The invention pertains to the field of blade tensioners. More particularly, the invention pertains to a blade tensioner with a blade shoe that is self aligning.
2. Description of the Art
A blade-type tensioner is used to impart tension on a chain. A blade-type tensioner generally includes a plastic blade shoe with an arcuately curved chain sliding face, a plurality of leaf-spring-shaped blade springs provided opposite the chain sliding face, and a metal base that swingably supports a proximal end portion of the blade shoe and that slidably supports a distal end portion of the blade shoe. During operation, a chain slides and travels along the chain sliding face of the blade shoe and a resilient force due to the elastic deformation of the blade shoe and the blade spring is applied to the chain through the blade shoe and proper chain tension is maintained.
In prior art Japanese patent publication no. 2000-234656, a blade tensioner having a pair of guide portions is provided on the base to guide the travel of the distal end portion of the blade shoe when the distal end portion slides on the base. These guide portions are formed integral with the slide surface on the opposite edge portions thereof and are bent along a direction perpendicular to the slide surface. Each guide portion has a convexly curved surface on the opposing side to the distal end portion of the blade shoe, thereby decreasing the sliding resistance between each guide portion and blade shoe, allowing smooth movement of the blade shoe to occur. The convexly curved surface of the guide portion is generally formed by ironing the guide portion several times prior to bending, making the manufacturing of the prior art blade tensioner laborious.